Hello!

Has anyone every ran into a problem, when implementing MAPI/HTTP network settings, Outlook 2013 clients are getting log in popups. Even when inserting username and password nothing happens, same popup reappears? Connection to the exchange server is lost after that. No obvious error event's are logged.

When changing connection back to RPC/HTTP Outlook clients work normally.

OWA and EAS continue to work in MAPI/HTTP, only Outlook 2013 dosent.

We have set the Authentication from NTLM to Negotiate and back, but nothing seems to help.

What helps, and only until you close Outlook, is new outlook profile. If you close Outlook the same password prompt comes back.

Have tried changing [HKLM\System\CurrentControlSet\Control\LSA] lmcompatibilitylevel=3 but didnt help.

Any thoughts appreciated.

• Edited by MadOll Tuesday, May 26, 2015 1:38 PM

Hi,

Generally, using MAPI/HTTP requires all Exchange 2013 Client Access Servers to be updated to Exchange Server 2013 SP1 or later. And make sure your outlook clients upgrade to Outlook 2013 SP1 or later.

Additionally, please make sure the MAPI over HTTP is configured correctly in server side. Please refer to the following article to check it:

https://technet.microsoft.com/en-us/library/dn635177%28v=exchg.150%29.aspx?f=255&MSPPError=-2147217396

On server side you can also use this command to test MAPI/HTTP connectivity:

Test-OutlookConnectivity -RunFromServerId Contoso -ProbeIdentity OutlookMapiHttpSelfTestProbe

And Configure the MAPI virtual directory authentication method to Negotiate using the following command:

Set-MapiVirtualDirectory -Identity "Contoso\mapi (Default Web Site)" -InternalUrl https://Contoso.com/mapi -IISAuthenticationMethods Negotiate

On client side, please confirm if outlook enable the MAPI/HTTP by checking the registry value Of the articles mentioned below:

https://support.microsoft.com/en-us/kb/2937684 

Additionally, please check the Connection Status while the issue occurs:

Open Outlook - press CTRL key - right click on the Outlook icon from right bottom corner taskbar Connection Status to check the connection.

Please notice the Server name, status, protocol and Type information.

For detailed information about MAPI/HTTP, please refer to the below blog :

http://blogs.technet.com/b/exchange/archive/2014/05/09/outlook-connectivity-with-mapi-over-http.aspx    

Best Regards,

David

Thank you for the quick feedback. :)

Microsoft Outlook 2013 Client version 15.0.4719.1001 MSO 15.0.4719.1000
Microsoft Exchange 2013 SP1 CU8 (Version 15.0 (Build 1076.9))

Outlook Anywhere is set to NTLM.

We use Load Balancer. Will try routing around the balancer, to see what happens.

MapiHttpDisabled registry key in Client computers is not set/present, so I assume MAPIHTTP is enabled. Or should we add it to the registry and set it to 0? Just in case?

Thank you David, will try some of you suggestion.